The two breeding stations in the garage of the City map used to be rats but they changed them to possums sometime around release :\ If you were to replace an NPC type with rats, then any of the breed stations that had that NPC should have a rat waiting instead, tho the humping animation ends up a little jank.

The maned wolf doesn't have inflation by default tho, so if you just switch him into a breeding station he'll stay slim even if you unload a dragon into him. He'll still churn up into a properly huge condom afterwards thou.